238 Wisconsin Academy of Sciences , Arts and Letters . 
layer of liquid, less than 1 mm. thick, appeared on the upper 
side of the rubber. In four hours all the camphor had gone* 
through the rubber into the pyridine, leaving a depth of solu¬ 
tion of only about 1 mm. on the upper side of the membrane. 
During the process the membrane became somewhat distended 
and bulged upward toward the camphor. 
46) In this case the arrangement was again like in No. 
42, except that CC1 4 was employed instead of alcohol. After 
about four minutes it was evident that the block of camphor 
was beginning to disappear. In forty-three minutes the whole 
block was gone, having passed through the rubber into the CC1 4 , 
leaving on the upper side of the membrane a camphor solution 
less than a millimeter deep. The membrane became distended 
and bulged upward. After four hours, the liquid on the upper 
side of the membrane was from 1 to 2 mm. deep. 
47) This experiment was also like No. 42 except that CS 2 
was used as the liquid instead of alcohol. After four minutes 
it was clearly evident that the block of camphor was being at¬ 
tacked. After 13 minutes a thin layer of liquid was visible 
on the upper side of the rubber. After 45 minutes all solid 
camphor had disappeared, having passed through the rubber 
into the CS 2 , leaving on the upper side of the membrane a solu¬ 
tion about 3 to 4 mm. deep. After four hours the membrane 
appeared very much distended, bulging downward, the liquids 
in and outside being on a level. 
48) In this case a cube of paraffine of rather high melting 
point (70 s ) was separated from 99.5 per cent alcohol by means 
of a rubber septum, the arrangement being as described in No. 
42. After 24 hours the lower comers and edges of the par¬ 
affine cube appeared slightly rounded. No liquid was visible 
on the upper side of the rubber, however. After three days 
the large bulk of the paraffine was still intact, though it was 
distinctly evident that the substance was slowly passing through 
the rubber septum into the alcohol beneath, without any* liquid 
layer appearing on the upper side of the membrane. 
49) This experiment was identical with the preceding one, 
No. 48, except that toluene was used instead of alcohol. In 
this case solution gradually accumulated on the upper side of 
